I agree with you. I want to play after the ending with a DLC, like Broken Steel. That way, if people don't want to play after the end, they don't have to download the DLC for it. Didn't Bethesda originally say that FO3 would have an ending, but a lot of people complained? It would make sense for them to add to the ending of this game as well.
No thank you.
I don't want to be presented with the choice of missing out on addditional content Or having the ending rendered meaningless.
If there is a play-after-ending DLC. It should unlock the ability to play after the ending. Nothing else. No new quests, items, weapons or locations and no gameplay changes.
Just the ability to continue.
That way those of us that prefer the ending to be a definite one don't have to make the choice I mentioned at the beginning of this post.